On 6/20/25 9:18 AM, Zhenzhong Duan wrote:
> When guest in scalable mode and x-flts=on, we stick to system MR for IOMMUFD
when guest works in scalable mode ?
> backed host device. Then its default hwpt contains GPA->HPA mappings which is
> used directly if PGTT=PT and used as nested parent if PGTT=FLT. Otherwise
> fallback to original processing.
>
> Suggested-by: Yi Liu <yi.l....@intel.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com>
> ---
> hw/i386/intel_iommu.c | 24 ++++++++++++++++++++++++
> 1 file changed, 24 insertions(+)
>
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index ed71bb8ec7..be01f8885f 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -1779,6 +1779,7 @@ static bool vtd_dev_pt_enabled(IntelIOMMUState *s,
> VTDContextEntry *ce,
> */
> return false;
> }
> +
spurious new line
> return (VTD_PE_GET_TYPE(&pe) == VTD_SM_PASID_ENTRY_PT);
> }
>
> @@ -1790,10 +1791,33 @@ static bool vtd_as_pt_enabled(VTDAddressSpace *as)
> {
> IntelIOMMUState *s;
> VTDContextEntry ce;
> + struct vtd_as_key key = {
> + .bus = as->bus,
> + .devfn = as->devfn,
> + };
>
> assert(as);
>
> s = as->iommu_state;
> +
> + /*
> + * When guest in scalable mode and x-flts=on, we stick to system MR
ditto
> + * for IOMMUFD backed host device. Then its default hwpt contains
> + * GPA->HPA mappings which is used directly if PGTT=PT and used as
> + * nested parent if PGTT=FLT. Otherwise fallback to original
fall back here and above
This comment sounds a little bit unrelated to the below implementation
which does not refer to system MR. how does the search for the hiod
relate to that. I would refocus the comment.
> + * processing.
> + */
> + if (s->root_scalable && s->flts) {
> + VTDHostIOMMUDevice *vtd_hiod;
> +
> + vtd_hiod = g_hash_table_lookup(s->vtd_host_iommu_dev, &key);
> + if (vtd_hiod && vtd_hiod->hiod &&
> + object_dynamic_cast(OBJECT(vtd_hiod->hiod),
> + TYPE_HOST_IOMMU_DEVICE_IOMMUFD)) {
> + return true;
> + }
> + }
> +
> if (vtd_dev_to_context_entry(s, pci_bus_num(as->bus), as->devfn,
> &ce)) {
> /*
Eric
